This invention relates to a power source apparatus for powering the driving motor of an electric vehicle, such as a hybrid car or electric automobile, and in particular, relates to a car power source apparatus which can accurately determine detection circuit malfunction with a simple circuit configuration.
To increase power source apparatus output to drive an electric vehicle, it is necessary to increase battery voltage. This is because power output is proportional to the product of battery voltage and current. For example, power source apparatus batteries for hybrid cars and electric automobiles are extremely high voltage at 200V or more. In a high voltage battery, a plurality of rechargeable batteries are connected in series to form battery modules, and those battery modules are again connected in series to increase output voltage.
In this type of battery comprising a large number of battery modules connected in series, it is important to charge and discharge each battery module while preventing over-charge and over-discharge. This is because over-charge and over-discharge degrade a battery's electrical performance and shorten its lifetime. A car power source apparatus has been developed to prevent battery module over-charge and over-discharge by detecting battery module voltage and controlling battery charge and discharge (refer to Japanese Patent Application Disclosure 2002-199510).